Robert McNeill Alexander


Robert McNeill Alexander, CBE FRS was a British zoologist and a leading authority in the field of biomechanics. Until 1970, he was mainly concerned with fish, investigating the mechanics of swim bladders, tails and fish jaw mechanisms. Subsequently, he concentrated on the mechanics of terrestrial locomotion, notably walking and running in mammals, particularly on gait selection and its relationship to anatomy and to the structural design of skeletons and muscles.

Education and early life

Born in Lisburn, Northern Ireland, Alexander was educated at Tonbridge School, Trinity Hall, Cambridge and the University of Wales. His PhD research was supervised by James Gray.

Career and research

After holding a lectureship at University College of North Wales from 1958 to 1969, he was Professor of Zoology at the University of Leeds from 1969 until his retirement in 1999, when the title of emeritus professor was conferred upon him.
Alexander was secretary of the Zoological Society of London which included supervising the management of London and Whipsnade Zoos. He was president of the Society for Experimental Biology, President of the International Society of Vertebrate Morphologists and editor of the Proceedings of the Royal Society B. Alexander specialised in research on animal mechanics and published numerous books and research papers in the field from 1959.

Dinosaur locomotion

Alexander was particularly interested in the mechanics of dinosaur motion. He developed a formula to calculate the speed of motion of dinosaurs, the so-called 'dinosaur speed calculator,' mathematically derived from the Froude number:
Originally, Alexander stated: "I have now obtained a relationship between speed, stride length and body size from observations of living animals and applied this to dinosaurs to achieve estimates of their speeds. The estimated speeds are rather low—between 1.0 and 3.6 ms−1."
Modifications to the original formula gave rise to revised estimates, and "Alexander argued that based on the bone dimensions of Tyrannosaurus it is unlikely they could have travelled at more than 8ms−1." Several calculations using variants of the formula indicate that dinosaurs probably travelled at around 3 ms−1 with a top speed of 8 ms−1. This translates to a speed range of roughly 6–20 mph.

Publications

Books

Alexander received several awards and honours during his career including:
Alexander married Ann Elizabeth Coulton in 1961. He died in 2016 at the age of 81.